武夷山黄山松群落能量的研究

在生物量,生产力研究的基础上,通过干重热值测定,对黄山松（Ｐｉｎｕｓｔａｉｗａｎｅｎｓｉｓ）群落的能量现存量,能量净固定量及太阳能转化效率进行分析讨论,测定结果表明,（１）黄山松群各组分样品的干重热值具有一定的差异,树皮的干重热值最高,为２２．１４ｋＪ／ｇ,枯根的干重热最低,为１６．２７ｋＪ／ｇ。（２）黄山松群落的能量现存量为３７９８３２．３ｋＪ／ｍ＾２,其中地上部分为２７５４８８．０ｋＪ／ｍ＾２     

森林溪流倒木生态学研究进展

溪流倒木是指在河流中长度大于1 m、直径大于10 cm的死木。溪流倒木在森林河流中(特别是较小的河流中)是一个常见且重要的结构成分。该文综述了近30年溪流倒木的研究成果(主要来自北美),总结溪流倒木在河流形态、碳循环、泥沙与养分拦截、水生生境的形成、水生生物多样性等方面的生态功能,倒木的时间动态性与空间变异性,以及干扰(包括自然干扰与人为干扰)与倒木存留量及分布的关系。此外,该文也探讨了溪流倒木的生态管理模式及未来研究方向。大量的研究证明,溪流倒木对森林水生生态系统具有重要的生态功能,但它的存留量、分布以及它的生态意义因所研究的森林生态系统、河流大小不同而异。随着河流宽度的增加, 倒木的存留量及它对河流的影响减少,并且倒木的分布以单个为主变为聚集体为主。单个倒木的直径则随河流宽度增加而增大。倒木也呈现十分明显的时间动态性,而这种动态往往是由大规模毁灭性的森林干扰(火、风倒等)所驱动的。研究倒木的时空变异性及自然干扰与人为干扰对倒木的不同影响对于保持倒木的生态功能是十分必要的。该文还对中国开展溪流倒木的生态研究提出一些建议。     

鼎湖山锥栗+黄果厚壳桂+荷木群落生物量及其特征

通过永久性地调查编目和生物量预测模型估算了鼎湖山季风常阔叶林锥栗＋黄果厚壳桂＋荷木群落植物现存量。结果表明：（１）群落植被生物总量为２９５．６４０ｔ／ｈｍ＾２,其中乔木层为２８６．０６１ｔ／ｈｍ＾２,灌木层８．９００ｔ／ｈｍ＾２,草本层０．３３０ｔ／ｈｍ＾２,层间植物０．３４９ｔ／ｈｍ＾２,分别占植被总生物量的９６．７６％、３．０１％、０．１１％和０．１２％。（２）乔木层生物总量中、树干、枝、叶和     

不同林地清理方式对杉木人工林生态系统的影响

在杉木中心产区福建尤溪建立径流场,进行不同林地清理方式对杉木人工生态系统影响的６ａ定位研究结果表明：炼山清理迹地导致林地严重的水土流失,炼山后的６ａ中要地的水、土、肥人分别达８７６７．３２ｍ＾３／ｈｍ＾２、３８．００ｔ／ｈｍ＾２、５２３．１６ｋｇ／ｈｍ＾２,分别是不炼山林地的３．１０、１９．７０、６．１０倍。两种清理方式林地流失量差异随时间推移逐年缩小,于第６年趋于一致,炼山具有短期激效效应,经雨     

低强度HeNe激光辐照人体外周血对淋巴细胞染色体影响的研究

本文通过低强度Ｈｅ－Ｎｅ激光以能量密度分别为１４．３１Ｊ／ｃｍ＾２（辐照５’）、２８．６２Ｊ／ｃｍ＾２（辐照１０）、５７．２４Ｊ／ｃｍ＾２（辐照２０）１１４．５２Ｊ／ｃｍ＾２（辐照４０）燠夫体外周血后,检测其淋染色畸变率（ＣＡ）,激光照射血样（能量密度由低到高）未照射血样ＣＡ分别平均为４．２９‰、３．９６‰、３．８１‰、３．５９０‰、４．１９‰、Ｘ＾检测无显著差异,说明低强度的Ｈｅ－Ｎｅ激光辐照人     

大兴安岭地区紫貂冬季生境选择的研究

１９９１～１９９３年在大兴安岭的呼中和图强区,采用雪地足迹跟踪法研究了紫貂（Ｍａｒｔｅｓｚｉ－ｂｅｌｉｎａ）冬季对取食和休息生境的选择特点,结果表明紫貂喜好植被演替晚期的林型,具体特点如下：（１）喜好中等到高等树冠盖度的乔木林地（Ｐ＝０．０００１）和混合型林地（Ｐ＝０．０２）,回避单一树种优势林地和空地。（２）对灌木盖度无选择性（Ｐ＝０．０９）,但喜好混合型灌木林地（Ｐ＝０．０３）。（３）取食时喜好下坡位及岸边,休息时选择上坡位（Ｐ＝０．００９）,且倒木、大胸径树和树根较多的生境,不选择坡向（Ｐ＝０．３９）。（４）对大树密度（Ｐ＝０．０００１）、落叶松基区面积（Ｐ＝０．００５）、大树胸径（Ｐ＝０．０００１）、落叶松胸径（Ｐ＝０．００１４）、倒木全长（Ｐ＝０．０００６）、倒木直径（Ｐ＝０．００１４）及倒木覆盖面积（Ｐ＝０．０００１）都有明显的正选择性,且休息对生境的选择强于取食。对小树密度取食时喜好中等密度（１．２１～１．８２棵／ｍ２）林地,而休息时回避高密度区（１．８２～３．０３棵／ｍ２）。根据上述结果建议在择伐过程中应当保留植被演替晚期的林型和胸径在４０ｃｍ左右的大树。     

长白山阔叶红松林优势树种的木腐真菌群落结构特征

木腐真菌是森林生态系统中非常重要的组成部分,能够降解倒木,实现生态系统中的物质循环。长白山阔叶红松林林分结构复杂,林内植物种类多样,倒木数量极多,为木腐真菌的生长提供了丰富的基质。为了解该林分中不同树种对木腐真菌的影响,本研究选取了长白山自然保护区25 hm2永久性大样地中325块20 m×20 m的样方,对样方中的木腐真菌进行了调查和记录,并对其中4类优势树种槭属、椴属、栎属和松属倒木上的降解真菌分别进行了统计和分析,结果发现:阔叶红松林中这4种优势寄主上的木腐真菌占所调查真菌总数的86.6%,物种数占总数95.3%,囊括了该林分中木腐真菌的绝大多数。但不同树种上的真菌种类有很大差别,4种树种上木腐真菌的种类韦恩图显示,这4类优势树种共有种类仅为7种,而各自独特种至少占本类树种倒木上真菌种类的25%,尤其松属上的独特种类数占松属真菌总数的45.7%。倒木的腐烂程度和径级对木腐真菌也有着极为重要的影响。不论哪个树种,腐烂程度为2级的倒木均生长有种类最多、数量最大的真菌;而径级大于10 cm的倒木也是木腐真菌的优先选择。     

小叶章草地生态系统结构与功能的研究Ⅳ能量的固定和分配

小叶章草在生态系统年净初级生产力为３０５７９。１７ｋＪ／ｍ＾２．ａ,其中地上净初级生产力占３７．６４％,地下净初级生产力占６２．３６％。不同植物器官（组分）的能量现存量差异很大,上部根占植物亚系统总能量现存量的５４．８７％,穗的能量现存量仅占０．０３％,其它器官的能量现存量从大到小依次为：茎＞叶＞根茎＞枯落物＞下部根茎＞死根。不同植物器官（组分）热值含量水平亦存在较大差异,以去灰分热值比较,由大到     

不同剂量的He—Ne激光对Raji细胞膜脂流动性的影响

本文采用荧光偏振法检测了不同剂量的Ｈｅ－Ｎｅ激光照射法对Ｒａｊｉ细胞膜流动性的影响,发现了０．０１Ｊ／ｃｍ＾２和０．５１Ｊ／ｃｍ＾２两剂量可使膜脂微粘度降低（Ｐ〈０．０５）。即其膜脂流动性升高;１．０Ｊ／ｃｍ＾２和２．０Ｊ／ｃｍ＾２的剂量脂微粘度无明显影响,即其膜流动性无明显化（Ｐ〉０．０５）,而６．０２Ｊ／ｃｍ＾２的剂量可使膜微粘度明显上升（Ｐ〈０．０５）。即其膜流动性明显下降。     

CO2激光辐射奶山羊精液生物学效应的研究

本研究表明,３．５７Ｊ／ｃｍ＾２和７．４Ｊ／ｃｍ６２激光组可以改善精液品质,提高精子的代谢功能状态,以增强精子活力,认为是最佳剂量;１４．２８Ｊ／ｃｍ６２激光组虽然对精子的代谢,活力有效应,但不能维持,认为是临界剂量;２８．５６Ｊ／ｃｍ＾２激光对精子的损害作用,认为是抑制剂量。     

溪流粗木质残体的生态学研究进展

粗木质残体（CWD）是森林或溪流生态系统中残存的超过一定直径大小的站杆、倒木、枝桠及根系等死木质物的总称,溪流CWD对于溪流生态系统的稳定,水生生物多样性,河槽形态及其变化过程有着重要的作用。对溪流CWD的产生和分类,溪流CWD对于溪流生态系统的稳定,水生生物多样性,河槽形态及其变化过程有着重要的作用。对溪流CWD的产生和分类,溪流CWD贮量,分布和动态,以及溪流CWD的功能和管理分别进行了总结,并指出应尽快在国内开展溪流CWD的研究和管理。     

On the Relationships between Ground-dwelling Spider (Araneae) Assemblages and Dead Wood in a Northern Sugar Maple Forest

Downed woody material (fallen logs) offers ground-dwelling spiders (Araneae) ideal sites for nesting and foraging, but little is known about what characteristics of dead wood influence spider assemblages. In a maple forest of Forillon National Park, in eastern Québec (Canada), spider assemblages on, adjacent to, and away from fallen logs were compared. We also tested how log type (coniferous vs. deciduous) and decomposition stage influenced spider assemblages. Sampling was done for an intensive four-week period using both litter samples and pitfall traps. A total of 5613 spiders representing 83 species from 16 families was collected. Spiders were affected by the presence of logs, as both species diversity and total number of individuals collected were significantly higher on the log surface compared to the forest floor. Ordination analysis revealed a distinct compositional difference between the spider fauna found on the wood surface compared to the forest floor. Wood type and decomposition stage had few significant effects on spider assemblages, except that less decayed logs supported higher spider diversity than logs in advanced stages of decay. Dead wood is clearly important for generalist predators such as spiders, further supporting the conservation importance of fallen logs in northern forest ecosystems.     

喀斯特森林常见树种倒木分解对土壤真菌群落组成及分布规律的影响

倒木是森林生态系统的重要组分,其分解调控着土壤的养分循环,同时也影响着土壤微生物群落结构。但目前鲜见关于倒木分解对土壤微生物群落影响方面的报道。选取贵州茂兰喀斯特常绿落叶阔叶混交林中处于轻、中和重度腐烂等级的狭叶润楠（Machilus rehderi）、枫香（Liquidambar formosana）、青冈栎（Cyclobalanopsis glauca）和圆果化香（Platycarya longipes）4种常见树种倒木为研究对象,以距倒木外围的3个不同水平距离（10cm、30cm和50cm）的土壤样品为实验材料,分析倒木树种、腐烂等级和距离对土壤真菌种类及多样性的影响。结果表明：1）喀斯特森林4种树种倒木所影响土壤真菌群落在门级分类上主要为子囊菌门、担子菌门和毛霉门,优势属有Mortierella spp.、Phlebia spp.、Pluteus spp.和Chaetomium spp.等;2）倒木的树种对土壤真菌群落相对丰度的影响有差异,圆果化香倒木下的土壤真菌丰富度Chao1指数显著高于青冈栎;3）随腐烂程度加深,4种树种倒木下的土壤真菌群落多样性呈显著增加趋势;4）土壤真菌群落丰度随着距倒木距离的增大（10-50cm）变化明显,如狭叶润楠影响的Pluteus spp.、Mortierella spp.和Ganoderma spp.,枫香的Chaetomium spp.,圆果化香的Mortierella spp.和青冈栎的Phlebia spp.和Oliveonia spp.等。本研究量化了喀斯特森林倒木所影响的土壤真菌群落组成及分布规律,在一定程度上为倒木分解与土壤微生物群落之间的作用机制的深入探索提供了科学依据。     

林冠附生物在森林生态系统养分循环中的作用

1　引　言林冠是森林生态系统中重要的组成部分。由于认识上、技术上和其它方面的原因 ,过去一直都把林冠当作“黑箱”来研究。近 2 0年来 ,随着对林冠生物多样性、林冠附生物在生态系统功能过程影响认识和研究技术上的提高 ,对林冠附生物的研究已逐步从个体水平转移到系统水平上。林冠现在被认为是一个适宜于许多动植物种类生存的场所 ,其物种数量比原先所想象的更为丰富。通过对林冠的研究 ,促进了对天然林生态系统中养分循环的了解 ,以及林冠干扰或破坏对自然和人类活动的影响。其中林冠附生物质在森林生态系统养分循环过程中的作用和影…     

Urban ecological footprints in Africa

Africa’s rate of urbanization is the highest in the world. This is relevant to ecologists working in Africa because urban growth is strongly associated with habitat destruction, and also creates new fields of study. The ecological footprint concept is used to illustrate how urban settlements in Africa impact on rural ecosystems. At an aggregate level, African countries have the lowest ecological footprints in the world. However, there is little available data for individual cities, so evidence is fragmented making concerted policy initiatives difficult. Wood fuel continues to be a major source of energy for urban households and there is a long running debate as to what extent providing wood fuel for urban use damages forest ecosystems. Growing evidence contests the assertion that urban wood fuel markets are responsible for forest degradation. Although there are other options available, the social consequences of switching energy sources need to be taken into account. Outright bans, for example on charcoal, would lead to a loss of livelihoods in rural and urban households, and may not solve deforestation as well as increasing fossil fuel use would increase the ecological footprint.     

Dendrochronological assessment of the time since death of dead wood in an old growth Magellan's beech forest,Navarino Island (Chile)

The present study investigated the relationship between time since death and the morphological characteristics of fallen dead trees in a Nothofagus betuloides forest stand located on the island of Navarino (Chile). In this unmanaged forest, there were 399 m³ ha^?1 of dead wood, which represented about half of the living tree volume. At the investigation site, 18 living trees were selected and increment cores were collected from them to build master ring‐width chronologies. Cross sections were also collected from 48 fallen dead trees. The samples collected were then assigned to observable decay classes and their death date was determined dendrochronologically. Cross‐dating techniques were used and it was found that the fallen dead trees cross‐dated significantly with standard chronologies. A year of death was successfully determined for 75% of the sampled fallen dead trees. However, this study demonstrated that, in the standard classification, the transition rate from one class of decay to another was highly variable. Furthermore, the inconsistencies found in the decay rates of the fallen dead trees demonstrated that the existing decay classification schemes were unsuitable for this type of forest stand and that the relationship between qualitatively assessed decay classes and the time since death of trees in this extreme environment was rather weak. In addition, the analysis of the time since death, in this old growth forest, was indicative of the persistence of dead wood on the forest floor in austral cold ecosystems and of its contribution to long‐term carbon storage.     

Seeing the forest for its multiple ecosystem services: Indicators for cultural services in heterogeneous forests

The ecosystem service (ES) framework is gaining traction in ecosystem management as a means to recognize the multiple benefits that ecosystems provide. In forested ecosystems, many structural attributes (trees, understory plants and woody debris) create heterogeneous ecosystems that provide numerous ecosystem services, including many that are culturally important. However, application of the ES framework to forest management is challenged by difficulties measuring and comparing multiple ES across diverse and heterogeneous forest conditions. Indicators can help bring the ES approach to forest management by providing a means for accurate ES inventory and mapping. We measured 10 forest ES in contrasting forest types to investigate the effects of past forest harvesting in coastal temperate rainforest of Vancouver Island, BC, Canada. Our objectives were to build a systematic set of ES indicators for coastal temperate forests based on forest structural features, including trees, coarse woody debris, and understory plants. To achieve this, we 1) analyzed field data to compare the effects of forest age (old-growth vs. second-growth) and ecological site conditions (riparian vs. upland forest) on the bundle of ES provided by different forest types; and 2) worked with a local indigenous wood carver to identify attributes of cedar trees (Thuja plicata) essential for traditional uses, including canoe carving. Forest age and forest type had significant and major effects on bundles of ES. Old-growth forests provided three times higher carbon storage, nine times higher wood volume, and eighteen times higher canopy habitat services than recovering forests. Within old-growth forests, the proportion of trees suitable for traditional indigenous wood carving was significantly higher in riparian stands. Yet of 456 trees measured, only 17 were cedar with potential traditional uses. Of those, trees for canoe carving were the least frequent (n = 3), which we identified as large (>110 cm DBH) trees of exceptional quality. In general, old-growth riparian forests were a hotspot of ES, providing for example nearly three times as much carbon storage as old-growth forests on upland sites and 12 times the amount of carbon storage as found in second-growth forests on upland sites. These results indicate that typical inventories of forest ES, which usually generalize across heterogeneity, may oversimplify dramatic variations in ES bundles in forested landscapes. Our novel set of stand-level ES indicators can improve the accuracy of ES assessments, incorporate important cultural ES, and help address the role of landscape heterogeneity in influencing ES.     

Suspended Dead Wood Decomposes Slowly in the Tropics,with Microbial Decay Greater than Termite Decay

Ecosystems - Coarse woody debris (CWD) is an important pool of carbon in forest ecosystems and is present in all strata as fallen, standing or suspended CWD. However, there are relatively few...     

大小兴安岭针叶树倒木上木腐真菌的物种多样性

木腐真菌在森林生态系统中具有丰富的物种多样性, 并在倒木的降解过程中发挥重要的生态功能。针叶树是大小兴安岭森林生态系统的优势树种, 因此研究针叶树倒木木腐真菌物种多样性和影响其物种分布的相关环境因子有助于揭示大小兴安岭森林生态系统物质循环的机理。本研究收集了近16年对大小兴安岭地区冷杉属(Abies)、落叶松属(Larix)、云杉属(Picea)和松属(Pinus) 4类针叶树倒木上1,561份木腐真菌标本的采集信息, 统计了物种种类及其腐朽类型, 并选取具有代表性的地点开展木腐真菌群落多样性及其与环境因子的相关性分析。结果显示, 大小兴安岭针叶树倒木木腐真菌有166种, 隶属于70属, 其中白腐真菌有111种, 占所有种类的66.9%, 褐腐真菌为55种, 占所有种类的33.1%。在4类针叶树倒木上均能生长的真菌种类有19种, 占所有种类的11.5%, 其中柔丝干酪孔菌(Oligoporus sericeomollis)是各类倒木上木腐真菌群落中的优势种。大兴安岭地区落叶松属为优势寄主, 其倒木上生长的木腐真菌种类数和个体数在4类倒木中均为最高; 而小兴安岭地区松属倒木上木腐真菌种类数和个体数比其他3类倒木高, 是该地区的优势寄主。对6个代表性地区木腐真菌群落的研究显示, 有11种真菌在6个地区均有分布, 小兴安岭地区木腐真菌多样性普遍高于大兴安岭地区; 聚类分析显示树种比地理位置对木腐真菌物种分布的影响更大。